1. Field of the Invention
The present invention relates to microscopes and related instruments. More particularly, the invention relates to a cordless microscope with an improved light source assembly.
2. Description of the Prior Art
Microscopes are commonly used in laboratories, classrooms, and other applications and are considered to be among the most valuable scientific instruments ever invented. To permit magnified viewing of a specimen, a typical microscope requires that the specimen be illuminated. Microscopes are arranged either for transmitted illumination, where light is passed through the specimen, or for reflected illumination, where light bounces back from the specimen. Transmitted lighting is more usual today.
Ambient or general purpose room lighting is typically not intense enough to provide the desired amount of specimen illumination; therefore, most microscopes include an electric lamp or other means of artificial illumination. Typically, the lamp is built into the base or stand of the microscope and is plugged into a conventional 120 volt AC outlet with an electrical cord. Unfortunately, such electrical cords cause several problems. For example, many laboratories and classrooms do not have an adequate number of available AC outlets in which to plug the cords. This necessitates the use of unsightly and bulky extension cords and multiple-outlet plug-in strips. Another problem is that researchers, students, and teachers often wish to move their microscopes from location to location, requiring the cords to be frequently unplugged and then replugged into new outlets. Microscopes with electrical cords also cannot be used outdoors and other locations where no AC electrical outlets are available.
Cordless microscopes have been developed to address some of the above-identified concerns. Unfortunately, however, currently-available cordless microscopes suffer from several distinct disadvantages. For example, because sophisticated microscopes use relatively high-wattage bulbs to provide adequate specimen illumination, a quality cordless microscope either requires a large battery to power the bulb or has a very short operating life between battery charges. Some cordless microscopes solve this problem by using lower wattage bulbs. While these types of microscopes are adequate for use as toys, they do not provide adequate illumination for most scientific and educational applications.
Another limitation of existing cordless microscopes, and all microscopes in general, is that they typically use tungsten, halogen, or fluorescent bulbs that generate a great deal of excess heat. Such heat may cause burns and may undesirably raise the temperature of any specimens placed in the vicinity thereof. The excess heat may be dissipated by fans, but this further increases the power requirements, cost, and complexity of the microscopes.
Another limitation of existing cordless microscopes, and all microscopes in general, is that their bulbs frequently burn out and/or break and therefore must be replaced. This necessitates a partial dismantling of a microscope""s base or stand to access, remove, and replace its bulb.
The present invention solves the above-described problems and provides a distinct advance in the art of cordless microscopes and microscopes in general. More particularly, the present invention provides a microscope having an improved light source assembly that provides sufficient illumination for sophisticated microscopic applications while requiring so little power that it may be operated with a small, rechargeable battery pack that provides over 40 hours of continuous operation from a single charge. The light source assembly has a bulb life of approximately 100,000 hours and operates at temperatures significantly below the operating temperatures of conventional microscope bulbs.
One embodiment of the light source assembly of the present invention broadly includes a circuit board, a plurality of Light Emitting Diodes (LEDs) mounted on the circuit board, and a connector configured for coupling with a rechargeable battery. The circuit board is preferably circular in shape and is coated with a reflective material to reflect light emitted from the LEDs. The circuit board fits within a circular opening in the base of a microscope and replaces a conventional microscope lamp.
The LEDs have a highly-focused angle of illumination, operate at a high candle power, and generate optimum true white light to provide an illumination approximately equal to that of a conventional 20-watt bulb. Advantageously, the LEDs require much less power than conventional microscope bulbs and operate at a much lower temperature. The light source assembly of the present invention therefore needs no cooling fan and can be powered by a small battery pack that provides for approximately 40 hours of continuous operation from a single charge. The LEDs have a bulb life of approximately 100,000 hours and therefore may never need to be replaced. In the event that the LEDs require replacement, the entire light source assembly can be easily removed from the microscope and replaced with another similar or identical light source assembly.
These and other important aspects of the present invention are described more fully in the detailed description below.